Problem: $\dfrac{2}{3} - \dfrac{5}{8} = {?}$
Solution: $ = {\dfrac{2 \times 8}{3 \times 8}} - {\dfrac{5 \times 3}{8 \times 3}} $ $ = {\dfrac{16}{24}} - {\dfrac{15}{24}} $ $ = \dfrac{{16} - {15}}{24} $ $ = \dfrac{1}{24}$